Police in Libya say unknown gunmen shot and killed a well-known human rights activist just after she cast her vote in Libya's parliamentary election Wednesday.

Attackers killed Salwa Bugaighis at her home in Benghazi. Her husband, who was in the house at the time, is missing.

Bugaighis was a lawyer who played a large part in the 2011 uprising that drove dictator Moammar Gadhafi from power. She also was an outspoken critic of Islamist extremists who have brought chaos to Libya since Gadhafi's overthrow.

State Department spokeswoman Marie Harf says the United States condemns in the strongest terms what she calls Bugaighis' senseless and brutal murder. Harf calls her a courageous woman and a true Libyan patriot.

Libyans voted Wednesday for a new parliament, casting ballots for 1,600 candidates running for 200 seats.

The new parliament will try to bring stability to a country where militias run rampant and have seized key oil exporting facilities.